What is the maximum production of purple batteries from the valley's resources?

So, here's my production: 12 purple batteries per minute. Another zone also produces 12 blue batteries per minute and 3 buck capsules per minute. I could add another 6 purple batteries per minute, but then 1) ore production won't keep up, and I'll have to periodically shut down this section. 2) energy consumption will increase, so I'll have to transfer energy to purple batteries, which kind of defeats the purpose of the additional 6-battery section; they'll all go toward production needs. At the same time, producing anything other than purple batteries and capsules seems pointless; energy consumption will increase without a significant increase in currency. How can I upgrade production? I understand that when moving to another region, you can transfer resources from there, but how can I min-max using only valley resources? I also don't really like that amethyst ore is not needed for anything at all; my consumption is literally 0. The plant layout may not be the most optimal, but resource consumption is 100% optimized. I don't see any way to make the production of 12 batteries take up less than the full length of a warehouse block.